Found in old American documentation, this circuit is current as it uses the 555 to modulate an infrared LED. Pulses are set by R1.
The signal itself captured by the (long) antenna serves to feed this simple experimental circuit....
This voltage level-triggered circuit was found in a 1969 Ferranti English documentation. Modern...
This amplifier makes use of a simple 12 to 30 W source, having been found in the SGS manual of...